1. Field of the Invention
The present invention relates to a side buffer for a conveying vehicle traveling along a ceiling and a conveying vehicle system.
2. Description of the Related Art
A semiconductor manufacturing plant includes a conveying system for conveying a container, in which substrates are contained, between processing apparatuses.
For example, the conveying system is provided with a rail suspended from a ceiling, and a conveying vehicle supported by the rail so as to be suspended therefrom. The conveying vehicle conveys a front opening unified pod (FOUP), in which substrates are contained.
Moreover, a side buffer is disposed adjacent to the rail so as to be able to adjust the timing for conveying the FOUP to the processing apparatus (See, for example, Japanese Patent Application Laid-Open No. 2009-196748).
The side buffer described in Japanese Patent Application Laid-Open No. 2009-196748 is described below. Note that, in the following descriptions about the technology described in Japanese Patent Application Laid-Open No. 2009-196748, reference numerals assigned to components are those used in Japanese Patent Application Laid-Open No. 2009-196748, and are not related to reference numerals which are illustrated in the drawings of the present application.
The side buffer described in Japanese Patent Application Laid-Open No. 2009-196748 includes an anti-tip member 350 in order to prevent a FOUP from falling from a placement table 300 due to shock caused by an earthquake, and the like.
The anti-tip member 350 has an angular U-letter shape. The anti-tip member 350 is constituted of a tilting restriction portion 350a, a connecting portion 350b, and a fixing portion 350c. The tilting restriction portion 350a, the connecting portion 350b, and the fixing portion 350c are integrally formed. The fixing portion 350c is a plate-shaped portion and is screwed to a beam 360 of the placement table 300. The connecting portion 350b is a plate-shaped portion extending upward from the fixing portion 350c. The tilting restriction portion 350a is a plate-shaped portion extending perpendicular to the connecting portion 350b. In other words, the tilting restriction portion 350a is displaced above a position where an article is placed on the placement table 300.
In Japanese Patent Application Laid-Open No. 2009-196748, an article 500 is the FOUP and includes a protruding portion 510 at the lowermost portion of aside portion. An abutment surface portion 510a is disposed on an upper surface of the protruding portion 510. When the article 500 is to be placed onto the placement table 300, the article 500 is moved by a conveying vehicle 3 in a substantially horizontal direction toward the placement table 300. During this movement operation, the position of the abutment surface portion 510a of the article 500 in a height direction is lower than the position of the tilting restriction portion 350a in the height direction. The article 500 is conveyed above the placement table 300 by this movement operation, and then is lowered so as to be placed onto the placement table 300.
When the article 500 tilts while having been placed on the placement table 300, the abutment surface portion 510a abuts against the tilting restriction portion 350a. Accordingly, the range of tilting of the article 500 placed on the placement table 300 is restricted.
In the above-mentioned placement table 300, the tilting restriction portion 350a is disposed above the portion where the article 500 is placed on the placement table 300. Therefore, the article cannot be moved in upward and downward directions between a position above the tilting restriction portion 350a and the placement table 300.
In a conveying system described in Japanese Patent Application Laid-Open No. 2009-196748, the taking-in and taking-out of the article 500 are performed at only one side of the placement table. This is because an edge of a lid of the FOUP protrudes from the side surface so that the lid of the FOUP would make contact with the tilting restriction portion when the taking-in and taking-out of the article 500 is performed at the opposite side of the placement table. Accordingly, the technology described in Japanese Patent Application Laid-Open No. 2009-196748 cannot be applied to a conveying vehicle system in which a FOUP having a lid protruding from the side surface is taken-in and taken-out at both sides of the placement table.